Real work, small boundary

Use real inputs, representative users, and a live workflow whenever risk allows. A demonstration with invented data answers whether a demo can be performed. It rarely answers whether the organization can create value.

Keep the boundary small. One product line, one queue, one document type, one customer segment, one internal team, or one recurring decision can be enough.

The right size is not the smallest technical build. It is the smallest test capable of producing credible business evidence.